Ball-bearing.



R. C MITCHELL.

BALL BEARING.

APPLICATION FILED JAN. 7, m5.

Patented Dec. 21,

2 SHEETS-SHEET R. 0. MITCHELL.

BALL BEARING. APPLICATIQN men mg. 1. ms'.

Patented Dec.21,1915.

. 2 SHEETS-SHEET 2.

' freely introduced.

sma rns reman enrich.

ROBERT GLMITCHELL, or moniv'r VERNON, New Yonx.

BALL-BEARING.

To all whom it may concern:

Be it known that I, ROBERT C. MITCHELL,

a citizen of the United States, residing at Mount Vernon, Westchestercounty, State of New York, have invented certain new and usefulImprovements in Ball-Bearings, of which the following is a full, clear,and exact description.

My invention relates to ball bearings and has particular reference to anrimproved bearing ring construction, the advantages of which will behereinafter described.

In the drawings-Figure 1' isa cross-section on an enlarged scale ofpartof one'of the, rings of a ball bearing containingmy improvement andshowing a part of a grinding wheel. jFig. 2 is a face view of that partof the ring shown in Fig. l, but before said ring is completed: Fig. 3is a similar view of the same part completed. Fig. at is a section ofthat portion of the ring shown in Fig. 1, that section being taken onthe plane of the line 44 looking in the direction of the arrow, thegrinding wheel being shifted from the position shown in Fig. 1.

Fig. 5 is an end view of a ball bearing complete. vFig. 6 is an edgeview of a. bal

retainer is not new, but is'preferably used to avoid friction'betweentheballs. Since the load carrying capacity and the durability of a bearingdepends largely upon the number of balls employed, itis desirable to useas many as possible. Since therings 1-2 are integral, it is clear thatonly about half of a full complement of balls can be That number may beobviously introducedby merely displacing the rings ecoentrically. Thebalance of the balls must be inserted when the rings are in operativeposition, and hence-notches are commonly eemployed through which suchballs are successively passed i yito the raceway. If such entrancemote/hes are full depth throughout, the balls may be intro- Specification of Letters Patent.

Patent ed Dec. 21, 1915.

Application filed-Tannery 7, 1915. Serial no. 897.

duced without straining. If not full depth, pressure is required, andthe passageof the several balls from the inner end of the nonfull depthnotch into the operative position so tends to cut a groove, which thoughslight,

tends to make the bearing noisy. For this reason, it is desirable tohave a'full depth side entrance notch. It should be borne in mind thatbearings of this type are made 55 with great accuracy, and it isobviously diflicult to form Side entrance notches which invarlablyextend to the exact full depth of the race-way groove. If they do notextend to the bottom of the groove then the afore- To siiidobjectionable strain occurs upoxl the as sembling of the notchintroduced balls. As already stated, my invention aims to producea notchwhich overcomes these difiiculties, and 'to provide a reliable methodfor producing such notches uniformly. To'that end I form each notch bytwo separate steps.

) In Fig. 2 I have shown at 5 what corresponds to an ordinary non-fulldepth notch.

I form this much of my new notch by a 8!) suitable tool which isrelatively small and rapid in action. This part of the notch is extendedas near to the bottom of the raceway as can be safely done when workingrapidly. I complete the notch after the race-way is ground, andpreferably by the grinding wheel utilized for the race-way. In grindingbearing rings of this type,the ring is set up in a suitable machine andis moved against the grinding wheel by a .proper mechanical meansmanually controlled. When the race-way grinding operation isoompletedand without disturbing the position of the wheel relatively to thebottom of the groove, "I turn the rinyg so as to present the inner endof the prslviously formed main portion 5 of the notch to the saidwheel,'and I then move the parts. so that the wheel will move laterallyrelatively to'the bottom of the race-way so as to form the inner portion6 of the notch (see Figs. 3 and 4-). The race grinding Wheel being muchlarger in circumference than the grinding wheel used for formingthe-part 5, acts not only to cut the notch down to the w mathematicalbottom of the race-way groove, but also removes the relatively abruptshoulders-at the inner end of the non-full depth notch portion 5 so thatballs I in traversing the inner end ofsaid notch will not pound. It isobviously ossible to move the. grinding wheel-7 entir y through I travelat all times upon a mathematical center line of the-rac'e-way, but thatthe oin'ts of contact shift from side to side 0 the side wall of thebearingirin at one side of the race, but the same is preferablywithdrawn as indicated by dotted lines in Fig. 1 after a sufiicientportion of the metal hasbeen ground away, to secure the fullfdepthefi'ect whereby strain isrelieved in inserting/ the notch introducedballs, and whereb the abrupt shoulders at the inner end 0 the notchportion 5 are removed; It is preferable to remove the grinding wheel atthis time to avoid unduly wearing one side thereof, becausethe mainfunction of that wheel v is to grind the race-way and accordingly bothsides of the wheel should correspond and be true; It is well known thatin actual practice in such bearings, the balls do" not that;

line according to the particular strains, to which the bearing issubjected. Such bearings are designed to withstand and do withstand notonly "radial. but also-axial and twisting strains. Again, while inbearings of this character it is commonto refer to the contact of a ballwith the race-way as a point contact, nevertheless, it is a fact that"under load each-ball tends to flatten, so that the point of contactunder load is really not a point; but a contact zone oi-suhstan-j tialproportions, in contrast to'a point. i For a I all of these reasons theball track in .the

race-way, instead of being a fixed line is,

in fact, a track of considerablewidthl and,

surface, area which increases with. use and wear. It is because of thisfact thatnotched bearings as heretofore made, whether the notches havebeen of the full.depth,-or oi" the nearly full depth, type, have beenrein-S tively noisy, owing to the. impact of "the balls againsttlierelatively abrupt shoulders at the inner-ends of the notches wheneverthe balls have traveled on the notched side of the race-way. By myimprovement, these relatively abrupt shoulders are removed, so;- that'even; though the balls travel at timesj on that side of the racerway andover the.

end of the-notch, there is no objectionable. impact, noise'or wear. Isaid that there is a very slight shoulder at I the inner end of thefinal cut or portion 6 of the notch, this is so slight andis. so'im-.

material after polishing,";that its presence is in no w'ayhbjectionable.,n i have shown my improvednotch as applied to the-outer ring where theballs'move on the inside of the circle, and where, in the absence of myimprovement, the ball impact I at the end of a notch of the old typewould be substantial. The same notch construction may be, if desired,used forthe notchon the outer side of the inner ring, but I'ha've foundthat in practice this is not always required,

because the balls moving on ,the outside of the circle of the inner ringhave ,less tendextending substantially to,

against the ='shoulders at theinnerend of an ordina notch either of; thefull depth or nearly full depth typei" I I It will be noted' 'the ballentrance notch is always formed i'n that face-of the ring in II ency tostrike with objectionable ifircewhich thia ball race-wayis located; thatthe;

main portion of: said notch leads intothe race-,way transversely fromoneedge of the i ring that the inner end of said notch is extended in j adirectiin'iv transversely to the said main portion and-llongitudinally-iof the r'aceway itself, and that'inall instances this specially formedinner end pf the; "notch I never extends'below the bottom ofsaid race--way, Thus, the balls are always properly. supported, and; ill traversethe inner end 1 of the notch wit out objectionahle'noise on resistance.

In 5 I have shown thebearin'g "com?- plete'and pi" the'type in which theballspacer and retainer is n e, bath should be, under j I stoodthatincertain types-fofjbearings dea s ace'r' may be c" added ther'ace-way. In all instances ted and the I balls pro than that'partofthenotch innnedia'tely' ad d of the notch serving to out downthe'objectionable relatively abrupt shoulders which i would otherwise.extend into. path of travel ofth'e balls.

- What Iclaim is'i I 1 1.- A ball bearing ring having the etfective anannular grooved race-way, and a'xball entrance chan-' ncl in that faceof the ring in which the race, 1 way relocated, said channel leadinglaterally 7 into one side of said. race-way, the inner end" of that artof said channel which extends" into sa'i groove being relativelyflatterand thereof, said innerend of said channel extendingsubstantially down to butnot below the hott'om'of said race-Way,groove-vabanbwias, a g' s' ii a an- While" it may, b

broader than that part immediately-outside 'nular grooved race-waythereinanj :a ball entrance-notch in the faceof-thering -in which saidrace-way'is located, the'fiiain' porlf non ofsaid notch leadin-intdseidrace-way transversely from one e go of the rinfg', themner endof said notch extending trans versely of said main portion andlongitudinally ofnsaid race-way;. saidini=1er end also bottom of saidraceway groove, part-oi but not below the 1 the main portion of saidnotch being less than the full depth of said racesway.

having anw-an- 3. In a ball bearing, a ring nular grooved race-waytherein and flit-ball entrance notch in the face of theriw inwhich'saidfrace-way isjlocated, the main "portion-pf said notch being ofless depth.

15 ing of less depth thanthe full depth of the than the full depth ofsaid'race-way and leading into said race-Way transversely from one edgeof the ring, the inner end of said notch extending transversely of themain portion and longitudinally of said race-way,

said transversely extended inner end also extending substantially downto, but not below the bottom of said race-Way groove.

l. In a ball bearing, a ring having an annular groovedn'aee-way thereinand a ball entrance notch .in the face of the ring in which saidrace-Way is located, the main portion of said notch leading into saidraceway transversely from each edge of the ring, part of the mainportion of said notch berace-Way, the inner end of said notch beingwider than that part thereof immediately to the rear thereof, said innerend also extending substantially to, but not below, the bottom of saidrace-Way groove. 5. In a ball bearing of the character described, a ringhaving a race-Way therein and a ball entrance notch extending from oneside of the ring to the;' bottom of the raceway, one of the shoulders atleast at the inner end of said notch being cut down adjacent to thebottom of said race-Way groove.

.ROBERT C. MITCHELL.

Witnesses:

. HENDERSON F. HILL, R. G. MITCHELL.

